error message

[Stephen Woodbridge]

John,

The way tileindexes work is the you group a bunch of files into a
virtual layer. All the files must have the same dbf columns defined in
them and defined in the same order. This is because mapserver reads the
attribute layout of the first file it opens and uses that as the
template for all files in the virtual layer.

So if the first file had attribute columns [A, B, C] and some other file
had [D, E] or [B, C, A] or whatever it would cause problems for
mapserver. If you ask mapserver to CLASS on C, it translates that to
column 3 and then tries to read column 3 from the [D, E] and gets an
error, or gets column A from [B, C, A] file, etc. This was causing a lot
of problems for people that did not understand the inner workings of
mapserver, so this check was added to prevent people from doing bad
things and not knowing about it.

Some version of dbfdump will display the column definitions of you
files. You either have some that have a different definition like a
different version of the file, or you are picking up some files that are
not compatible with the first file you add to the index.

Hope this helps,
   -Steve W.

John Bolster wrote:

> Hello,
>
> Does anyone know what "DBF fields do not match" means in the output from
> tile4ms?
>
> Do they not match to one another, or to a certain way they're meant to be,
> or to the shapefile, or what? The files were created with tgr2shp so I don't
> see why they should be bad. And what would I do about this--I can't imagine
> I'm the only person to whom this has happened.
>
> Thanks for your help,
> John Bolster
>